Apparatus for hard disintegrating and sifting



April 18, 1961 G. cLAEs 2,930,347

APPARATUS FOR HARD DISINTEGRATING AND SIFTING Filed April 17, 1958 INVEN 1-0;? M 3 W United States Patent APPARATUS FOR HARD DISINTEGRATING AND SIF'I'ING Georg Claes, Ennigerloh, Westphalia, Germany, as-

signor to Firma Gebr. Hischmann, Maschinenfabrik, Ennigerloh, Westphalia, Germany, a corporation of Germany Filed Apr. 17, 1958, Ser. No. 729,215

Claims priority, application Germany Apr. 18, 1957 3 Claims. (Cl. 241-34) The present invention relates to the hard-disintegration and sitting of goods to be ground, whereby goods to be ground which have been prebroken are fed to a rotary grinding device which comprises substantially a mill and a sitter.

It is one object of the present invention to provide a method of hard-disintegration and sitting, whereby not only a quite better efficiency is brought about for the used mills and sifting devices, but in addition a qualitatively improved final product is also achieved.

In the known methods for hard-disintegration and sifting of goods to be ground, as for instance a cement clinker, the goods to be ground which have been prebroken in a preliminary mill are fed directly to one or a plurality of fine mills. In a sifting system which is disposed behind the mills the coarse grain portion is sep arated from the fine grain portion and is returned again to the fine mills. This known method has the drawback that prebroken goods to be ground are fed to the fine mills, which prebroken goods to be ground had already an appreciable portion of fine grain. The added fine 335 grain portion reduces appreciably, however, the efficiency of fine mills, since, as it is well known, the greatest labor has to be used in the mills for the conveyance of the goods to be ground, for the friction loss and for the elas tic forming work.

1 In another known method these drawbacks are partly removed by an arrangement according to which the goods to be ground which have been prebroken in a preliminary mill are fed to a sifting device which is coupled in accordance with the series principle with one or a plurality of fine mills. The coarse grain portion which has been separated in the sifting device is fed to the fine mills and the goods which have been further broken up inthe fine mills are returned to the sifting device, so that a continuous cycle takes place of the coarse grain portion through the mills and the sitting device. This known method has, however, also the drawback that the finest grain portion in thefine grain portion is extremely low in spite of the unfavorable efiiciency, which fact causes, for instance if used for cement, a low quality. All known methods have the additional drawback that due to irregular feeding of the apparatus with the prebroken goods to be ground, the fine mills and the sifting device are subjected to appreciable load fluctuations,so that upon overloading with the goods to be ground, not only the machine parts and the driving motors are overloaded, but the goods to be ground are broken up in ap- .1 Finally, the known methods have inherently also the drawback that separate mill devices had to be provided V for the production of dilierent qualities of goods to be ground. a F

. It is, theref ore, one'object of the present invention to provide a method of hard-disintegration and sifting of goods to be ground wherein the prebroke'n goods, prior to their entrance into the rotary milling devices, are fed from a storage bunker to a preliminary sifting device by means of an adjustable conveyor device and are separated into a fine grain portion I and a coarse grain portion I and the coarse grain portion I is fed either directly or through an intermediate bunker to the rotary milling device, where it is further broken up and is separated into a fine grain portion II and a coarse grain portion H, whereby the coarse grain portion H is returned to the fine mills through the intermediate bunker.

This method in accordance with the present invention has at first the advantage that in addition to achieving a highly dispersed final product, the efiiciency of the apparatus is appreciably increased compared with the known apparatus.

The high efficiency is brought about in such a manner that the grain portion which has been reduced to the desired final fineness is separated in the preliminary filling device, so that the fine mill is no more charged with the fine grain portion I. The fine mill is thus charged exclusively with the insufficiently reduced coarse grain portion I and the coarse grain'portion II.

Furthermore, in accordance with the present invention the prebroken goods to be ground are fed to a rotary device over a conveyor device which is adjustable in aecordance with the specific mill efiiciency. The control of the conveyor device may be brought about, for instance, by a bunker indicator, indicating the level in said bunker, which indicator is disposed in the intermediate bunker and responsive to the degree of the filling of the bunker. There is, however, also the possibility to obtain the control by means of an acoustic ear-which conveys impulses to the drive of the conveyor device depending upon the degree of filling of the mill or by means of a mechanical or electrical load measuring device in the conveyor device which is disposed behind the fine mill.

In advantageous manner the best filling degree may be maintained for a particular rotary milling device. Load fluctuations due to irregular feeding cannot occur anymore with an apparatus constructed in accordance with the present invention.

A further advantage is brought about by the present invention by an arrangement according to which in addition to the-actually dispersed fine grain portion 11, simultaneously a low dispersed fine grain portion I-isprovided. This is of particular importance, for instance :in

cement milling apparatus, where difierent cement.

qualities are desirable which are distinguished from each other merely by their degree of finenessu,

In accordance with the present invention it is thus possible to provide, in an advantageous manner, 'a plurality of cement qualities by using a single milling de Finally, the present invention brings about also the. ad

vantage'that the method may be performed with the most diiferent mills, siftingdevices, a swell as conveyor-dev ces. I H With this and other objects inview which will become apparent in the followingdetailed description, thepresentinvention'will be clearly understood in conn with the accompanying drawings, in which:

Figure l is a schematic showing of a grindingapparatus 1 designed in accordance with ,the presen invention; aiid' Fig. 2 is a schematic 'showingof a' rindin sppsrams Patented Aer-18. 7961.

f" "g "I t, j

clfesig necttn accordance with Referring'now to the drawings, it may be readily asfis ftaingdihak he; an a at s cl sc me n-fi s. V and 2; co 2 vely,

s'pectively, i r

Th-F3 3l Pa 3t91di Q iQl bilerates inlthe follow; ingmanner: i ,7 r 7 11 cqarsa aia tor din-me bunker iris fed to the te imi ammil 3 nan exact do agetand previously de rfii mi heconveyor band. scale 2"which ped withaafweight indicator.' The thus prebgokengogds runlover an elevator elevator'4 tolthe' QQBEQQU KH 6i I'Ih'epreliminarymill 3 is of such measurements that ha, s "ia greater iw'orlging: capacity;than that;

' o ;melater anangedmeant.10,: It is possibleithereby 3 4. ia gfilql antities of prebroken goods are availv m. 1116, SIOtage'bunker-Qthat the fine rnilllfl may'ruig to: stay t i threetshifts; while the: preliminary mar- 3,; 7

9! ns ns sf lmsonlytin one or two Ishifts; J

v The: prebroken goods erconvyed from the i adage bunker fi'by; means of. aiconveying' device 7, operated by econtrqllahlemotor 8;t91the preliminary sifting 'devicef9.

The -prebri0k111goodk are separated in said preliminary siiterr 9ifto aifinegrain portion I' and a coarse graintportion I. Whilethefiuel'grain portion I is now fed to some parrticulariusage, the coarse grain portion I is ,fed, to" the chamber'll' of the .multi-chamber compound mill 10.

is Th'e multi-chan'iberl compound mill 10 is divided into two chambers 11 and 12 bymeans of a centrally dis posed'separatingwall; The mill 10 is ied by a connecting branch disposed at each end side thereofi'while the ground goodsmre removed substantially from the center of the f about, for instance by thel'use of a short tubular; mill 3. The gojofds are,h'o.w'e'ver, ground much finer'in the fine mill 10iand thelproportion ofifinest;grain andathe specifie mill 'lfl. and are Vfedthrough-a-housing 13. 7

'The coarse grain'portionl' fed into th'e lcha'rnber .movestowarditheicentereof the fine mill 10 andisthere;

V J the present invention having afe'edingrun different from that'shown in Fig. l.

' conveying device 7so that the best degree of the fine mill '10 is automatically restored.

v a r a 4 4 I t indicator 18 registers such change; which indicator-18 in turn sends an electrical impulse over the electric conduit 21 to'the driving motor 8 off't'he conveying'device 7 and,

thereby slows down or accelerates the conveying device 7, depending upon a predetermined level of the coarse grain in II fi eh intemied a unker 6 7 7 Bysuch control it is; arranged-that in case of an bverload of the fine mill it) 'due to'a greater quantity flow'of materialjthe level 17a is raisedin the intermediate bunker 16 and thereby lowers the amount of conveyance in the filling for An eq al zed f ed n maybe bta ne howe e or tance al n" silch a m n er t aousfic e is provided adjacent' the mill 10, as is known already, which causes impulses to the l notor 8 for the conveying device 7 created by the sound depending upon the degree of filling ofthe mill-10; Thus, instead of the level indicator, the

a u ica i ,.p 0 d w ic pe d nt p n' ind?-v ing noises, which constitute a measure of the] filling of h mill 0 Qn t CQHH L impulse to h m t r 8, a s:

ing, respectively, acceleration and retardation of the latter.

Incase of sueharrange ment thefleyel, indicator'18 and the intermediatebunlier 16s are eliminatedfrom the direct i v t l h Q; .9 t at 8 direct cycleis created w en th mend the si dev ceils. TAnother embodiment of the control device may be of Sash eq stwc'tiontha -a cn'si grm ans n f rm of a load me e t 'Q i Z' i -n' ov dcd: in: the ey l hi is disposed, between themin -10; and :the sitting. device} 15,,

twhich-load nteterlii depcndinglupontheload, that means dependinguporythe amountvof the'igoods. emerging from :the 1D sendselectrical impluses: through th'e'conduit 2110.111: mqtorlsiot heic'onyeying device 7. Such load meter-23n1ay be:constructed as a'weight'meter or as an .electricatpowejr meter, which is connected with thedriv- V i tmotor 8for, the elevator; J

' The fine grain portion I'removedfront the" preliminary siftin'g'device 9rrnayr be fed'to a particular use, for instance with a very small proportion of fine'st grain, which fine grain portionl may constitute the'jquality I. The

' smaller, proportionlof finestgrainin the fine grain-portion h'y mean's of an elevator14. The main sifting deivie; 15

H sparates-the'jnely ground goods to a finegrain portion II; which -may be removed tor particularuse and into a ai-coarsegrain portion;-I I.'

The coarse grain portion II Hi hi an e qfrthe quantities for such flow is measuried by the 09 6 ans of ran-electrical conduitll with the t ,Softheijcdiivefihg device. 7. h d n a p e e ermined I rbecrne stab g is shown in Fig. 1 oi-the drawingsrthe" total coarse grain portion} moves into the cha bee 11bi the fine millj-lhflsince, howeventhe flow, of the; coarse- "gr ain- 'portion I; is smaller in qtlantity-than that of the I coarse-grain portionfllgafportion 'of-ethe coarse grain-f portion-ITmust befed--towardsflthe"rnill-chamber 11 ffor fthe p'rp'se of:hhbquliZedlmilLload; The'ratio 4 t a .7 teamed e rie mmfrq; a1$h66vn3iiiFig$2,- eveljndicator 18%isfdis' P ed titheilintemedie t nk n 16, w ch in t millf lfl =arethenjconveyed-to the'maiusifting device 15 f is fed to an intermediate vbunker,16wh'ejrethe goods are'divided irttwo conveying devices 19; Nina-predetermined ratio to jthe two'charn-z I and the smallers'pecific surface, respectively, is broilght surfacejiis, therefore, i'a ppr'eciably higher; .The; fine grain portion-H is, therefore} fed ft'o'sonie particular use suite ably as" impr vgea' quality. II. he i uality'l is achieved 7 from thefine 'graimportion Ifdue. to -itscoarser grain, and

quality 'II Tisachie'ved fromz t he fi'ne grain portion IL There;is'yet thepossibly to intermix the finegrainpor tions II-and} andthus to produce-a final product of mediumgquality or "to coordinate both. sifting devices 9 and 15' to each other'so 'that theylproduceth'esarne quality. T Referring'now' to Fig.; Zj'the second apparatusidifiers fro m'the one disclosed in Fig. 1 ,faside'frorn the particular means for controlling thernoto'r; 8,}imerely by the :arrange- "menti'that' the coarsegrain' portio I separated in the 5 prelimin ry sifteif9f' of the reiolvingQmilling' devicejjvhich comprises-the fine' mill' 10',the .elevator14', theimain' sifting'device15fand thebinterrnediatebunker 16', is not "*fed thr'oughgthe 'finemill'16 but'throughthe-intermediate bunker16;YBy thi s'arrangement, the coarse igrain por rtion lxisi 'suitably mixed with,tlieicoarsegrainportion if, in Q'Oraerto divide equally the' fraction proportions Furi i'n' the sa'rne manner as;

thermore, this apparatus operat ments are given by example only and not in a limiting sense, the scope of the present invention being determined by the objects and the claims.

I claim:

1. In an apparatus for reducing and sifting of goods to be ground, means for pre-breaking said goods, a preliminary sifting device, first means including driving means for conveying said goods discharged from said pre-breaking means to said preliminary sifting device, a fine grinding mill, an intermediate bunker having variable discharge means, a first discharge means of said preliminary sifting device adapted to discharge a first fine grain portion of a first order, second means for conveying a discharge of a first oarse grain portion of a first order from said preliminary sifting device to said fine grinding mill, third means for conveying said goods from said intermediate bunker to said fine grinding mill, a main sifting device, fourth means for conveying the discharge of said fine grinding mill to said main sifting device, a second discharge means of said main sifting device adapted to discharge a second fine grain portion of a second order, and fifth means for conveying a discharge of a second coarse grain portion of a second order from said main sifting device to said intermediate bunker, and a single sensing means responsive to the quantity produced of said fine grain portion of a second order for controlling said driving means of said first conveying means.

2. The apparatus, as set forth in claim 1, wherein said fourth conveying means include an elevator having a driving motor and said sensing means being responsive to the load of said fine grain portion of a second order conveyed by said elevator.

3. The apparatus, as set forth in claim 1, which includes a sixth means for conveying said coarse grain portion of said first order directly to said fine grinding mill.

References Cited in the file of this patent UNITED sTATEs PATENTS 

